Octatosylaminophthalocyanine: a reusable chromogenic anion chemosensor

Detailed herein is the use of 2,3,9,10,16,17,23,24-octatosylaminophthalocyanine as a chromogenic chemosensor for anions. The host:guest complexes formed during the sensing event can be regenerated by acid treatment without loss of the sensing ability. This allows the phthalocyanine chemosensor to be reused. This system also responds in a colorimetric manner when exposed to the neutral solvent molecules, dimethyl sulfoxide and methanol. A single-crystal X-ray structure of the Pc 1:2 MeOH complex was obtained. It illustrates the main interactions between the host:guest species in the solid state. Fits of the binding curves are consistent with this stoichiometry predominating in the solution state

Photodynamic inactivation of a RNA-virus model using water-soluble β-octa-Substituted pyridinium-pyrazolyl phthalocyanines

Among the various groups of microorganisms, viruses have generally a greater capacity for mutation, especially RNA viruses, as was demonstrated by SARS-CoV2 virus mutations. This high mutation rate promotes the development of their resistance to traditional antivirals and establishes the resistance behaviour in virus populations, decreasing their susceptibility to these drugs. In this context, the photodynamic treatment appears as a potentially effective method against microorganisms and, considering its mode of action is not likely to lead to the development of resistance. In this work, two newly zinc(II) phthalocyanines (ZnPcs) bearing pyridinium-pyrazolyl groups (2a and 3a) were synthesized, characterized, and applied in photodynamic inactivation (PDI) of bacteriophage Φ6 (or Phage Phi6) as a RNA-virus model. These quaternized dyes were applied at different concentrations (from 5.0 to 20 μM, and under white light irradiation in the irradiance range between 50 and 150 mW/cm2) to test their efficiency for possible clinical or environmental applications. The results showed that the new cationic ZnPcs 2a and 3a efficiently inactivate the RNA-virus model (bacteriophage Φ6), even at the lowest tested irradiance. These compounds are thus promising photosensitizers to be used in various contexts.info:eu-repo/semantics/publishedVersio

Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

<p>Abstract</p> <p>Background</p> <p>In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in <it>meso</it>-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (<it>Enterococcus faecalis</it>) and of a Gram (-) bacterium (<it>Escherichia coli</it>). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.</p> <p>Results</p> <p>Bacterial suspension (10⁷CFU mL^-1) treated with different photosensitizers concentrations (0.5, 1.0 and 5.0 μM) were exposed to white light (40 W m^-2) for a total light dose of 64.8 J cm^-2. The most effective photosensitizers against both bacterial strains were the Tri-Py⁺-Me-PF and Tri-Py⁺-Me-CO₂Me at 5.0 μM with a light fluence of 64.8 J cm^-2, leading to > 7.0 log (> 99,999%) of photoinactivation. The tetracationic porphyrin also proved to be a good photosensitizer against both bacterial strains. Both di-cationic and the monocationic porphyrins were the least effective ones.</p> <p>Conclusion</p> <p>The number of positive charges, the charge distribution in the porphyrins' structure and the <it>meso</it>-substituent groups seem to have different effects on the photoinactivation of both bacteria. As the Tri-Py⁺-Me-PF porphyrin provides the highest log reduction using lower light doses, this photosensitizer can efficiently photoinactivate a large spectrum of environmental bacteria. The complete inactivation of both bacterial strains with low light fluence (40 W m^-2) means that the photodynamic approach can be applied to wastewater treatment under natural light conditions which makes this technology cheap and feasible in terms of the light source.</p

Diketopyrrolopyrrole-fullerene C60 architectures as highly efficient heavy atom-free photosensitizers: Synthesis, photophysical properties and photodynamic activity

Chromophore-fullerene C60 hybrids possess interesting properties that enable them to act as heavy atom-free photosensitizers and reactive oxygen species (ROS) producers. Here, two new diketopyrrolopyrrole-C60 conjugates were efficiently synthesized and characterized. The conjugates show broadband absorption in the visible spectral region, in which diketopyrrolopyrrole dyes act as light-harvesting antenna with very high capacity to populate excited triplet states. Furthermore, the ability of diketopyrrolopyrrole-C60 systems to generate singlet molecular oxygen was explored for the first time in solvents of different polarities. The experimental results show that these architectures exhibit very high production rates of this ROS. In addition, a preliminary study on Staphylococcus aureus cell suspensions indicates that both conjugates exhibit phototoxicity after irradiation with green LED light. Thus, the data obtained provide evidence that these diketopyrrolopyrrole-C60 architectures act as potential heavy atom-free photosensitizers in photodynamic inactivation of microorganisms and other singlet oxygen-mediated applications.Fil: Agazzi, Maximiliano Luis. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Almodovar, Vitor A. S.. Universidade de Aveiro; PortugalFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Bertolotti, Sonia Graciela. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Tomé, Augusto C.. Universidade de Aveiro; PortugalFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Discovery of thiazolo [5,4-c] isoquinoline based compounds as acetylcholinesterase inhibitors through computational target prediction, molecular docking and bioassay

We thank Nathalie Reichmann and Leendert Hamoen (University of Amsterdam) for critical reading of the manuscript, Ana Velic (Proteome Center Tübingen) for help with proteome analysis and Mike VanNieuwenhze (Indiana University) for the generous gift of HADA. This study was funded by the European Research Council through grant ERC‐2017‐CoG‐771709 (to MGP), by national funds through FCT– Fundação para a Ciência e a Tecnologia, PTDC/BIA‐MIC/6982/2020 (to HV); PTDC/BIA‐PLA/3432/2012 (to SRF); FCT through MOSTMICRO‐ITQB R&D Unit (UIDB/04612/2020, UIDP/04612/2020) and LS4FUTURE Associated Laboratory (LA/P/0087/2020) and FCT fellowship SFRH/BD/147052/2019 (to BMS); by the Swiss National National Foundation through P300P3_155346 (to AJ); by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement No 839596 (to SS) and by the European Molecular Biology Organization through award ALTF 673‐2018 (to SS). Figure 6D and Appendix Fig S7 were created with Biorender.com .A computer-aided drug design (CADD) approach was developed for a focused chemical library comprising a series of sixteen thiazolo[5,4-c]isoquinoline derivatives. Little is known about this group of heteroaromatic compounds, both from the point of view of their synthesis and their biological properties. First, our CADD approach included target prediction by Mondrian conformal prediction with the ChEMBL database. The acetylcholinesterase (AChE) was identified as having a high probability of thiazolo[5,4-c]isoquinolines being active against it. Secondly, the molecular docking predictions revealed four promising thiazoloisoquinolines (2, 7, 13 and 14) according to their prominent ligand-protein energy scores and relevant binding affinities with the AChE pocket residues. The subsequent in vitro evaluation of promising hits and related ones revealed a set of novel AChE inhibitors. Therefore, the findings reported herein may provide a new strategy for discovering novel AChE inhibitors.publishersversionpublishe

Exploring the reactivity of formylporphyrins with 3-(diethylamino)phenol. Synthesis, spectroscopic properties and singlet oxygen generation of a new porphyrin–rosamine conjugate

The design of novel molecular structures with tunable photophysical properties is an important research field for many applications including optoelectronics, sensing and bioimaging. Porphyrin and rhodamine/rosamine derivatives are among the most studied and relevant chemosensors and imaging probes due to their attractive photophysical properties, such as high absorption coefficients and long emission wavelengths. In this work, we present the synthesis and the structural characterization of a new porphyrin–rosamine conjugate H2P3 and its related triarylmethane precursors H2P1 and H2P2. The photophysical properties of H2P1, H2P2 and H2P3, and their ability to chelate iron(III) and copper(II) ions, were evaluated by absorption and emission spectroscopy. The formation of copper(II) complexes was confirmed by electron paramagnetic resonance (EPR), which also allowed the detection of an intense and stable radical signal for the free-base H2P3. Further studies involving the addition of the 2,2,6,6-tetramethylpiperidine spin trap to derivatives H2P1, H2P2 and H2P3, showed that only H2P3 gives rise to an EPR detectable signal due to a strong generation of singlet oxygen.publishe

Antimicrobial Photodynamic Therapy: Study of Bacterial Recovery Viability and Potential Development of Resistance after Treatment

Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process

Photodynamic Antimicrobial Chemotherapy in Aquaculture: Photoinactivation Studies of Vibrio fischeri

BACKGROUND: Photodynamic antimicrobial chemotherapy (PACT) combines light, a light-absorbing molecule that initiates a photochemical or photophysical reaction, and oxygen. The combined action of these three components originates reactive oxygen species that lead to microorganisms' destruction. The aim was to evaluate the efficiency of PACT on Vibrio fischeri: 1) with buffer solution, varying temperature, pH, salinity and oxygen concentration values; 2) with aquaculture water, to reproduce photoinactivation (PI) conditions in situ. METHODOLOGY/PRINCIPAL FINDINGS: To monitor the PI kinetics, the bioluminescence of V. fischeri was measured during the experiments. A tricationic meso-substituted porphyrin (Tri-Py(+)-Me-PF) was used as photosensitizer (5 µM in the studies with buffer solution and 10-50 µM in the studies with aquaculture water); artificial white light (4 mW cm(-2)) and solar irradiation (40 mW cm(-2)) were used as light sources; and the bacterial concentration used for all experiments was ≈10(7) CFU mL(-1) (corresponding to a bioluminescence level of 10(5) relative light units--RLU). The variations in pH (6.5-8.5), temperature (10-25°C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (≈7 log reduction). The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter. Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 µM of Tri-Py(+)-Me-PF. CONCLUSIONS/SIGNIFICANCE: If PACT is to be used in environmental applications, the matrix containing target microbial communities should be previously characterized in order to establish an efficient protocol having into account the photosensitizer concentration, the light source and the total light dose delivered. The possibility of using solar light in PACT to treat aquaculture water makes this technology cost-effective and attractive

Lanthanide compounds containing a benzo-15-crown-5 derivatised [60]fullerene and the related [Tb(H2O)(3)(NO3)(2)(acac)]. C14H20O5 supramolecular adduct

Novel lanthanum(III), europium(III) and terbium(III) compounds of a benzo-15-crown-5 [60]fulleropyrrolidine were isolated in the solid state and characterised using vibrational (infrared and Raman) spectroscopy and by 13C CP MAS NMR for the lanthanum(III) compound. The photoluminescence properties were investigated for the europium(III) and terbium(III) compounds. The related [Tb(H2O)3(NO3)2(acac)] C14H20O5 [where acac ¼ acetylacetonate and C14H20O5 ¼ benzo-15-crown-5] supramolecular adduct was isolated using similar synthetic conditions, in the absence of [60]fullerene, and its crystal structure used as a model for the coordination sphere of the lanthanide [60]fullerene derivatives, with further supporting evidence given by photoluminescence measurements